Let me start here: it really is a dangerous old world out there. The United States does have legitimate strategic and economic interests around the globe; there are those who would very much like for us not to have them. And the biggest military power in the world does bear some responsibility to weigh in when something ghastly is going on, like chemical warfare against civilians or genocide.

So I am not going to argue here that the U.S. is always the Black Hat, or that we are a maniacal imperialist juggernaut, or any of the other standard left castigation of American usages of power. I have done so about specific instances of such usage, such as the disastrous Bush Iraq con job/fiasco. Nearly every American use of military force during my lifetime has been a tragic mistake, in my opinion. But I’m not going to argue–nor do I believe–that the United States is overall or in every instance a force for evil in the world, nor that any use of military might is wrong. I believe such a position to be uninformed and naive.

If I lost you there, you should probably stop reading this now.

However, it is starting to look to me as though there is less and less of a point to such extensions of military power, because they don’t work.

It is remarkable how few wars in recent decades have been “won” by anyone but the home team. During the era of empire, it was routine for European powers–and later, the U.S.–to march into any backwater it pleased, fling about a bunch of bullets and shells, and then run up the flag. Whatever local resistance was proffered never amounted to much to worry about, which had the deleterious effect of encouraging more of this behavior.

Since the second World War, however, that kind of outcome has become increasingly rare. More often, guerrilla insurgencies and indigenous resistance have made “winning” impossible, and holding areas in dispute debilitatingly expensive in both lives and treasure. If you don’t think things have changed, consider Belgium’s savage and near-instantaneous conquest of the region now known as the Democratic Republic of Congo and compare it to the mess the United States finds itself mired in in Afghanistan.

You can draw a line from Korea through Southeast Asia and into Central America, Afghanistan (twice), Iran and Iraq, and Ukraine, and the common denominator is that militarily superior invaders and proxy armies have simply been unable to hold territory they think they have won. The moment–sometimes within minutes–they turn their backs, that territory is back in the hands of popularly supported insurgencies.

As I see it, there are two major drivers of this. One has been with us forever, but the second is brand-new to the latter half of the 20th, and now the 21st century.

PROXY GAMES. The first is the principle of a proxy war, in which Greater Powers battle using smaller ones as proxy armies. The Korean War was a fine example: the US and its allies were fighting the Chinese in that war, yet we still don’t really talk about it in those terms. Today, Ukraine is shaping up as a fine opportunity for a proxy war, though the fact that it is so close on the doorstep of Russia means Western powers may decline to play.

WEAPONS, WEAPONS EVERYWHERE. This is the more important point, and one I don’t hear anyone else talking about. Empires used to win their colonial wars of conquering because they had better arms and training. That is still, by and large, true, but there is a matter of diminishing returns. If everyone in a country you are trying to invade has an AK-47 and one in every 25 has a rocket-fired grenade launcher, it doesn’t matter how superior your weapons are: you still can’t hold a hostile population that is armed to theteeth. It’s impossible. You would need a 1-to-1 soldier to inhabitant ratio even to attempt it, and you’d have to commit massive civilian slaughter in the process.

Since the second World War, the United States and its allies (like the UK, France, Sweden and Israel) have been the arms merchants to the greater world, and China and the USSR/Russia have done their best to follow suit. World arms trade is staggering in scope, and is the lion’s share of so-called “foreign aid” provided around the world.

The result has been a world awash in weapons. So many, in fact, that even though the “good stuff” is carefully guarded, it simply doesn’t matter. Unless you have the hearts and minds of most of the population of the area you are trying to occupy–in which case, you probably don’t need to be fighting a war in the first place–you cannot possibly hold and stabilize a significant region of the modern world, because pretty much every native population of areas under conflict is thoroughly armed with weapons of enough sophistication and enough deadliness to make it impossible.

Yes, we make lots of money selling death technology. So do our friends, and so do our enemies.

But when it comes to war, the outcome of this tidy business is that we are hoist on our own petard.